The invention concerns a roller tappet comprising a housing near whose drive side front end, two diametrically opposing flats receding from an outer wall of the housing are arranged, each of said two flats comprising a seat with a U-shape open in a direction towards the drive side front end, a pin being mounted in said seats, a roller serving as a run-on surface of a periodic stroke producer extending on said pin, a support for a tappet follower element being seated axially under the roller near a driven side front end of the roller tappet, a retention means in an axial direction of the pin and a retention means in the seats for the pin being provided for preventing the pin from exiting axially out of the housing.
A roller tappet of the above-cited type, for example for a high pressure fuel pump of a quality or quantity regulated type internal combustion engine is described in DE 10 2010 022 318 A1. A retention means for the pin for preventing its exit out of the housing is created through its encompassment over more than 180° in the seats of the flats. At the same time, the pin runs with its front ends on inner sides of an upper belt zone of the housing so that a further retention means is created (s. FIG. 4).
A drawback of the aforesaid configuration is that, during snapping-in of the pin into its seat, a plastic deformation of its only thin-walled sheet material, as well as surface damage, can occur. Depending on the circumstances, if the encompassment of the pin is inadequate, this type of securing can also come apart. Moreover, it is to be noted that when the pin runs with its front ends on the inner sides of the upper belt, wear can likewise occur so that, in the final analysis, it is not possible to adjust the axial lash of the pin.